Air separator



Feb. 23, 1932. E, RAMER 1,846,210

AIR SEPARATOR Filed Jul 29, 1929 Patented Feb. 23, 1932 UNITED STATES PATENT OFFICE mm 01' BERLIN, GERMANY, ASSIGNOR 1'0 THE FIRM HAIR-TSTOIF-M'EIALL LITIE'NGESELLSCHAFT, OF BERLIN -COPE1\TICK, GERMANY AIR snmaaron Application filed July 29, 1929, Serial No.

My-invention relates to a wind sifter or a winnowing machine in which a lurality of obli as guide plates is provide above one not er in step-like arrangement, the disintegrated substance or material to be sifted or separated or winnowed bein conducted downwardly over said plates and additional wind or air being conducted upwardly through the spaces between the said plates so that the particles of the respective substance or material and the air cross and intersect one another whereby a particularly great sifting or separating or winnowing effect is attained.

The chief effect of the new arrangement is, however, this that the sifting or separatin or winnowing is carried out so thorough y that the etficiency of the machine is rendered extraordinarily high, even if the particles have only once made their way through the machine. a

For a correct estimate of this im roved machine one must bear in mind that t e efliciency of the known wind sifting or winnowing machines becomes very low when the charges they receive are comparatively large; this is true also of machines of the type in which the particles are fed upon and over quickly rotating circular plates or disks, and in order to attain a tolerably satisfying sifting with machines of this type it is necessary to ass the particles more than once through t e machine whereby correspondingly more time and driving power are consumed.

Matters are, just the reverse in this improved machine in which the material need be passed once only through the machine, the particles being thereby separated into 40 fine and coarse ones, the latt :r being practically nearly completely free of fine particles,

that is to say, they contain only traces thereof. This remarkable effect renders it possible to connect this improved sifting or 45 winnowing machine directly with mills, for instance coal mills, without impairing their action and efiiciency by comparatively large amounts of fine particles being conducted back into the mill together with the coarse to particles which are to be ground again.

382,042, and in Germany August a, 1928.

Concerning the present improved machine it is at once possible and, in fact, suited to its proper action to introduce the ground. particles, i. e. the mixture of fine and coarse particles into the Sifter casin by means of the same current of air that1as been used for removing that mixture from the mill. As the speed of the air becomes considerably reduced when ,it passes from the mill over into the sifter, the greatest part of the 00 particles falls down upon the up ermost plates and slides down to the succeeding-oblique plates and so on from plate to plate over the entire set thereof, the air current flowing at first in the same direction. 05

Now, tests have disclosed the fact that in case of a large amount of the ground material, especially if the material is of low specifiq gravity, as, for instance, coal, even a strong discharge wind coming from the mill is not 7 able to effect a satisfying sifting or winnowing in the sifting or winnowing machine, and another part of this invention consists, therefore, in supplying the sifter or winnowing machine with an additional current of air which 7 is supplied separately below the lowermost plate or plates and fiows through the spaces between the plates counter to the main current orcurrents by which the particles are carried into the apparatus. The upper current and the lower current are preferably conducted first into lateral passages left etween the walls of the casing and the oblique plates, and from said passages the currents pass through said spaces to a common discharge tube through which the fine particles are carried away, whereas the coarse ones are re-introduced into the mill, as is more fully described hereinafter.

, The invention is illustrated dia rammati- 9o cally and by way of example on t e accompanying drawings, on which Figure 1 is a vertical section through a sifting or winnowing machine designed according to this invention, and

Figure 2 is partly (upper half) a side-view of the same machine and partly (lower half) a vertical section through it, this section being taken at an angle of with respect to Fig. 1. v

The construction shown in these figures is particularly compact and intended for the treatment of big amounts of disintegrated materials.

In horizontal section the casing of the machine is quadrangular, and its interior is subdivided into two equal chambers 6 and 7 by means of a vertical wall 2, there being formed in this way, as it were, two adjacent sifters, but having a common discharge tube 3 for the fine particles separated from the mixture of the disintegrated particles carried into said chambers at the top thereof through two pipes 4 and 5 by means of the current or currents of air coming from the mill.

The particles pass over oblique guide plates 10 and 11 onto vertical sets of long guide plates 8 and short guide plates 14 which alternate in the manner shown in Fig. 1, the particles passing from the uppermost or first plate 8 to the uppermost or first plate 14, from this to the next or second plate 8, from this to the next or second plate 14, and so on, the fine particles being carried away on this way by the currents of air which first flow into the lateral chambers 12 and 13 from which. the air escapes through the slots between the plates. 14 and 8 to the inner passages 17, the upper ends of which terminate into the discharge pipe 3 through which the fine particles are carried away y the air to any suitable collecting chamber, receptacle, or the like.

It is obvious that the disintegrated particles are subjected to the action of the currents of air as often times as this air is subdivided by the slots mentioned; every time when the particles fall from any one of the oblique plates to the succeeding one, the finest particles are whirled up in the form of dust which is instantly seized by the air and is carried away into the discharge pipe 3; besides, the air tears from the coarser particles the fine ones, and so on from the top part of the machine to the bottom part thereof where, finally, the remaining particles which are to be returned to the mill fall through slots 20 and 21 into the discharge hopper 22. These slots 20 and 21 are located at the ends of .particularly long oblique plates 18 and 19 extending from the lower edge of the central plate 2 and forming between them a prismatic space.

Because of the provision of the inwardly directed oblique plates 14, the downwardly moving particles are led over all outwardly drawings. The

directed oblique plates 8, so that all these latter plates can haye the same length; in other words: it is not necessary that, as with other sifters of the general type, the lower plates are longer than those above, whereby the diameter of the apparatus is unduly increased. This is obviated in the present im proved sifter, as appears distinctly from the relative arrangement of the plates 8 and 14 is, of course, such that they form between them slots of ample size for the passage of the particles of the disintegrated material, as well as for the passage of the air or the like.

The passages 16 and 17 are separated from one another by the vertical wall 2, the object of which is to prevent whirls or eddies by the individual currents arriving from the left and from the right. The lefthand currents are collected and conducted upwardly, as are also the righthand currents, and only in the discharge tube 3 they meet in parallel direction.

Concerning now the large prismatic space between and below the long bottom plates 18 and 19, there extends through this space a tube 23 which, in the example shown in the drawings, is of diamond-shaped cross-section and is provided in its two lower walls with obliquely directed slots 25 which can be opened or closed more or less by a suitably shaped slide 24 to which is attached an adjusting handle 26. This tube serves for the supply of the additional amount of air above mentioned. This air is distributed first uniformly in said prismatic space and fiows then with uniform speed throu h the slots 20 and 21 upwardly (as indicate by the lowermost arrows in Fig. 1) into the passage 12 and 13 where it encounters the other currents of air cooperating therewith in the sifting. That additional air is particularly suited to increase this action in that it is not yet laden with particles'of dust so that the separating efiect and with this the efficiency of the apparatus is greatly increased. The strength of this action of the additional air can be regulated by means of the slide 24, as will be clear without more detailed description.

If the air ways are closed circulation ways into which the mill as well as the sifter, are inserted, the air being thus used alternately in the one apparatus and then in the other apparatus, and so on continually, it might seem possible that more or less fine particles get deposited in the tube 23. This is, however, not possible, firstly on account of the obliquity especially of the lower walls of that tube, and secondly, because of the provision of the slots just in the trough-forming lowermost part of the same. Fine dparticles carried into the tube 23 are carrie away by the air when it leaves this tube, and are returned to the sifter from which they' escape through the tube 3, whereas coarse particles drop down into the hopper 22 from which they are returned to-the mill.

The air pressure within the casing 1 is quite uniform in spite of the subdivision of this casing into two sifters. Firstly, the air figing "into the casing, or into the two sifters, through the pipes 4 and 5 arrives from a common place, viz.'the mill, secondly, the lengths of the ways between the chamber 6 and the passage '12 on the one side arid the chamber 7 and the passa e 13 on the other side are ual; v. and thirdly, a so the lengths of the ways m the tube 23 to the tube 3 are equal, so that thesifting roceeds in both sifters perfectly uniform and the efiect is entirely the same.

I claim:

1. In a sifting device, the combination of a closed casinlf adapted to be mounted on a lo indin mi lurality of superposed gphced gblique platgs in alternating re ation and of opposite obliquity and spaced from the walls of said casing roducin a lateral chamber, means for con ucting t e ground 15 material from the mill to the top p ataby means of a rising current of fluid carrying said material and entering said lateral chamber,'and means for supplying a counter flow of fluid from below the bottom plate to said 20 chamber.

2. In a sifting device, the combination of a closed casin adapted to be mounted on a grinding milfi a plurality of supe spaced oblique plates in alternating re ation 51;; and of opposite obliquity and spaced from the walls of said casing roducin a lateral chamber, means for co ucting t e ground material from the mill to the upper end of said chamber by means of a rising current so of fluid carrying said material and entering said lateral chamber, and means for supplying from below the bottom plate a counter flow-of fluid to said chamber. Y

3. In a-sifting device, the combination of 3 a closed casing adapted to be mounted on a grindin mill, a plurality of spaced superposed o lique plates in alternating relation and of opposite obliquity and spaced from the walls of said casing roduc' a lateral -.a chamber, means for con ucting tfie ound material from the mill to the tofp ate in said casing by a risin current of carrying the'material to sifted and entering said lateral chamber, and an apertured tube QJ traversing the open space below the bottom late in said casing for supplying a counter ow of air to said chamber. 4. The combination as specified in claim 3, including a means for controlling the cross- 53 sectional area of the apertures in said tube;

5. The combination as specified in claim 1, including a substantially vertical partition wall dividin said easing into two substantially equal c ambers, the superposed oblique plates in each chamberbemg spaced'both mm the walls of the chamber and said par titifin wall leaving open passages along said" we s.

In testimony whereof I aflix my si ature.

, ERWIN KR R. 

